Measurement of "Reed to Room"-Transfer Functions

Abstract

A method is proposed here to synthesize the acoustic response of a room to a musical reed wind instrument with tone holes played by a musician. The procedure uses convolution of a) two measured pulse responses and b) the mouthpiece pressure during playing. The novelty of the approach is to include the sound radiation directivity of the source in the impulse response measurement of the room by using the wind instrument's air column as an exciter. At the reed input end of the air column pressure pulses at typical peak pressures of several kilopascals are generated using a compressor and a solenoid valve, which provides a high SNR even at distant measurement positions. For auralization purpose, the source signal measurement is done very close to the sound generation locus, i.e. inside the mouthpiece. Because this measurement is largely insensitive to room acoustics, the proposed method can be considered a very convenient alternative to music recordings in anechoic conditions. As a proof of concept we report here experimental results for the case of a bassoon. The method can be extended to auralizations of reed and lip-reed musical instruments in virtual acoustic scenes, and sheds light on the importance of the reflective and radiative properties of the air column for the sound coloration.